Ontario Mineral Inventory

Ontario Geological Survey
Permanent Link to this Record: MDI000000000196

Record: MDI000000000196

General

Commodities

Primary Commodities: Gold

Location

Township or Area: Connell

Latitude: 51° 31' 39.16"    Longitude: -90° 5' .63"

UTM Zone: 15    Easting: 702300   Northing: 5712525    UTM Datum: NAD83

Resident Geologist District: Thunder Bay North

NTS Grid: 52O09SE

Point Location Description: Location from assessment file map in AFRO# 2.32421.

Location Method: Data Compilation

Assessment Work on File

Geology

Province: Superior

Subprovince: Uchi

Terrane: North Caribou

Domain: Uchi

Belt: Pickle Lake

Geological Age: Mesoarchean  

Geology Comments

Dec 19, 2006 (Mark Puumala) - The Tarp Lake area gold prospects and occurrences are located in the northern portion of the Pickle Lake Greenstone Belt. These occurrences are found within a mafic metavolcanic rock dominated supracrustal sequence identified by Young (2003) as being part of the > 2860 Ma Pickle Crow Assemblage. According to Young (2003), the Pickle Crow assemblage is dominated by massive and pillowed mafic metavolcanic flows with subordinate (likely synvolcanic) gabbroic sills. MacTavish (2006) describes the mafic metavolcanic flows as being commonly well-foliated to schistose, amphibolitized, and often finely-amygdaloidal. In addition, MacTavish (2006) indicates that the mafic metavolcanics include units of pillow and hyaloclastite breccia. The gabbroic sills are described by MacTavish (2006) as fine- to coarse-grained gabbro, melagabro and ferrogabbro sills up to 200 m thick. The mafic metavolcanics are intercalated with thin, laterally continuous banded iron formation and small, discontinuous lenses of intermediate to felsic metavolcanics. A significant 90 to 125 m thick northeast-trending unit of felsic to intermediate tuff breccia to pyroclastic breccia has been reported in this area by MacTavish. Relatively thin units (up to 70 m thick) of clastic metasedimentary rocks have also been reported by MacTavish (2006). All lithologies are intruded by semi-concordant feldspar porphyry dikes. These dikes are reported by MacTavish (2006) to vary widely in thickness and lateral continuity. MacTavish (2006) also indicates that all lithologies are crosscut by late biotite lamprophyre dikes that are up to 5 m in thickness. One of these dikes is reported to contain ultramafic and country rock xenoliths, red garnets and greenish diopside. Stratigraphy in the Tarp Lake area generally faces toward the northwest, except where asymmetric folding (mainly further to the southeast in the Pickle Crow mine area) has caused reversals in the younging direction (Young 2003). The dominant geological structure in the Tarp Lake area is the Tarp Lake Shear Zone. This structure strikes northeast and forms a wide, diffuse and anastamosing deformation zone that is poorly exposed and characterized (MacTavish 2006). The mafic metavolcanic rocks affected by this shear zone are characterized by moderate to intense carbonatization, sericitization and local silicification (MacTavish 2006). This alteration zone hosts the numerous gold occurrences throughout the area. Many of the more significant gold prospects appear to be located where the Tarp Lake Shear Zone is intersected by splays and/or later fault/shear zones, or relatively competent lithological units such as porphyry intrusions, gabbro and iron formation. The cross-cutting deformation zones are most commonly reported to strike approximately northwest, east-west and north-northeast. Similar complex faulting/shearing patterns have been noted nearby by MacQueen (1987) in the vicinity of the Pickle Crow gold mine, and by McAuley and Winter (1990) in the vicinity of a number of gold occurrences in the July Falls area.

Lithology

Mineralization

Mineralization Comments

Dec 19, 2006 (Mark Puumala) - The Esso Zone is described by McIvor (1991) as being located in a broad zone of intense hydrothermal alteration within a predominantly mafic metavolcanic rock sequence. Several 060-striking, near-vertically-dipping sulphide, oxide and silicate facies iron formations occur within these alteration zones. Diamond drilling by Esso Minerals and Homestake Canada between 1988 and 1998 has identified a silicate facies iron formation that contains anomalous gold values over appreciable widths in an area covering a strike-length of 240 m (McIvor 1991) and to a depth of 165 m (Panagapko 1997). The limits of the zone are defined by ddh 89-CB-01 and CB-90-04 to the southwest and ddh CB-90-07 to the northeast. The limits of the mineralized zone are interpreted by McIvor (1991) to be controlled by faults. MacTavish (2006) indicates that Homestake described the mineralization as consisting of chert-sulphide layers containing mainly pyrrhotite, within strongly-carbonatized and sericitized mafic to intermediate metavolcanic rocks. Significant assay results reported from this prospect include 9.5 g/t Au over 1.2 m in ddh 89-CB-02, 4.33 g/t Au over 3.4 m from CB-90-02, 2.10 g/t over 4.7 m from ddh CB-90-03, 3.07 g/t over 4.6 m from ddh CB-90-11 and 2.29 g/t over 1.5 m from ddh CB-97-01 (MacTavish 2006).

Mineral Record Details

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For detailed information regarding this mineral record please contact the Thunder Bay North Resident Geologist District Office